1. Field of the Invention
The present invention relates to a multi-carrier radio communication system and, more particularly, to a radio communication system, radio transmission apparatus and radio reception apparatus for error correction in retransmission.
2. Description of the Related Art
In a conventional retransmission control scheme in multi-carrier communication, a mobile station and a base station generally perform the following processes (see, e.g., Jpn. Pat. Appln. KOKAI Publication No. 2004-104574). The mobile station measures a reception channel quality for each carrier or carrier group, and transmits information about the measured reception channel quality to the base station. When an error is found in received data from the base station, the mobile station issues a retransmission request to the base station. Upon reception of the retransmission request, the base station transmits retransmission data to the mobile station. In this case, the base station transmits this retransmission data using a carrier other than the carrier or carrier group determined to be unusable based on the reception channel quality. The mobile station then demodulates this retransmission data.
However, in the above-described prior art, a channel response estimation means is required to accurately determine channel responses. A large overhead is also required to feed back, to the transmission side, the information of the channel responses and carrier to be used. Additionally, it is a challenge to increase a system throughput in communication, and decrease a processing amount for retransmission control and channel response estimation.